Windows (registered trademark) printer driver is a representative example of print control programs for controlling a printer. An installation set for the Windows (registered trademark) printer driver includes a catalog file called a CAT file for the printer driver. The catalog file stores an array of hash values of files included in the installation set. An electronic signature can further be appended to the catalog file. If the stored hash values are compared with the hash values of the files in the installation set after verifying the electronic signature appended to the catalog file, it is possible to verify whether contents of the files within the installation set are modified.
Meanwhile, some users want to customize printer drivers in accordance with an environment into which a print system is introduced. In particular, with recent diversification of environments into which print systems are introduced, usage of printer drivers has also been diversified, and there is a growing demand for customization of printer drivers. To respond to such a demand, Japanese Patent Application Laid-Open No. 2006-309724 discusses a customization technique that allows initial setting values displayed by a printer driver by default to be modified and that enables input control of setting values which the user can set through a user interface (UI) of the printer driver.
When a printer driver is customized using a method discussed in Japanese Patent Application Laid-Open No. 2006-309724, a printer driver is created in which some setting files in an installation set for the printer driver have been modified. The created printer driver includes, in addition to the setting files that have been modified through the customization, unmodified driver module and catalog file.
Thus, it is of significance that a driver is created in such a form that allows a customized driver to be installed by itself. If the aforementioned created driver includes only the setting files that have been modified through the customization, a user needs to prepare a separate driver module. Therefore, the user needs to manage the modified setting files and a driver module in association with each other, which increases load on the user. Accordingly, in a conventional technique, a driver is created in a form such that a customized driver can be installed by itself. Since the user can carry out an installation operation with ease, such a customized driver may be considered a user-friendly driver. However, the setting files of that driver have been modified, and thus the driver is in a state where the hash values of the setting files do not match with the hash values written in the catalog file, or in other words, a state that lacks consistency between the catalog file and the installation set.